Abnormal limb and trunk movements are seen in many children with cerebral palsy. Recognizing the difference between types of these movements is not well understood. This study aims to describe how common are these movements in children recruited from a population-based sample of children identified on a cerebral palsy register, and to explore associations with motor abilities. It is hoped this will lead to improved understanding and recognition of movement disorders in CP, to allow clinicians to choose appropriate treatments. We hypothesise that the underlying prevalence of dyskinesia is higher than that previously identified through conventional motor descriptions in cerebral palsy populations in Australia, and may approach 20%.